The serial effect of iodinated contrast media on renal hemodynamics and oxygenation as evaluated by ASL and BOLD MRI

Contrast-induced nephropathy is a prevalent cause of renal failure, and the mechanisms underlying this injury are not fully understood. We utilized noninvasive functional MRI in order to determine the serial effect of a single administration of iodinated contrast media (CM) on renal hemodynamics and oxygenation. Fifteen rabbits were randomized to receive an intravenous injection of CM (i.e. iopamidol-370; 6?ml?kg-1 body weight) or an equivalent amount of 0.9% saline. Both arterial spin-labeling and blood oxygen level-dependent imaging sequences were performed at 24?h before and at intervals of 1, 24, 48 and 72?h after injection to obtain serial renal blood flow (RBF) and relative spinspin relaxation rate (R2*). Results showed that, in the iopamidol group, the mean cortical RBF decreased at 1?h (p?=?0.04 vs baseline), reached its minimum at 24?h (p?=?0.01) and gradually returned to baseline by 48?h (p?=?nonsignificant, NS). The outer medullary RBF decreased to its minimum by 24?h (p?=?0.00) and remained less than baseline until 72?h. R2* in inner stripes was dramatically increased at 1?h (p?=?0.00), remained elevated at 24?h (p?=?0.05), but returned to baseline by 48?h (p?=?NS). R2* values within the cortex and outer stripes and inner medulla were slightly increased, but the changes did not reach a statistical significance (p?=?NS). Saline did not produce positive change in either RBF or R2* within different compartments of the kidney. We conclude that iopamidol is associated with a relatively longer-term hypoperfusion in whole kidney and decreased oxygen level in the inner stripes of the outer medulla. Copyright (c) 2012 John Wiley & Sons, Ltd.